Personal body armor has been utilized by military and law enforcement personnel as a means of providing personal protection from bullets, fragments and other missiles. Personal body armor designs and configurations must, due to their ultimate end-use, be both light-weight and flexible.
Personal body armor designs attempt to provide a lightweight flexible configuration that prevents penetration of the projectile into the human body and minimizes both backside armor deformation and the transfer of transfer of energy into the human body.
Traditional vehicular armor designs and configurations utilize rigid armor panels and/or plates constructed of a variety of materials including but not limited to metallic, ceramic, composite, fiberglass, nylon, aramid fiber and semi-crystalline polyolefin structures. Vehicular armoring materials and components must be lightweight structures capable of defeating anticipated projectile threats. The armor structures must transfer the kinetic energy inherent in the moving projectile so as to prevent penetration of the projectile and armor material spall (projectile and armor fragments) through the backside of the armor.
Vehicular armor designs attempt to provide lightweight configurations that prevent penetration of the projectile and resultant spall material through the backside of the armor. Vehicular armor structures are utilized on a variety of vehicles including but not limited to ground vehicles, aircraft, ships, etc.
All armor designs and configurations designed to defeat projectiles and missiles attempt to accomplish one or more of the following:
(1) Deform, bend, or dull incoming projectile to increase projectile area in contact with the armor in an effort to blunt and decelerate PA1 (2) Destabilize projectile by decelerating, deflecting, fracturing or changing projectile attitude (yaw) PA1 (3) Utilization of armoring materials and thicknesses that constitute an overmatch condition. (Condition where projectile cannot possibly defeat or penetrate an armor configuration due to type and thickness of material.
Armor construction techniques also employ a layer of a finely divided substance within a shell of a hard or relatively hard material, such as, for example, to absorb effectively the kinetic energy of an impacting projectile. However, these techniques have not been entirely successful. Other techniques employ the use of a group of metallic members or the like which are retained within a metallic matrix for assisting in the deflection of a projectile from its predetermined path upon impact.
U.S. Pat. No. 2,723,214 teaches that in order for the armor to work effectively, at least the relatively small plates forming the outermost layer of the armor must be sufficiently rigid to prevent their being pierced or severely bent, so as to permit one of such plates when struck by a projectile, to move therewith in order to compress and thus transmit force through an adjacent layer of resilient material. It is asserted that as a result, kinetic energy of the projectile is converted into potential energy stored within the successively compressed layers of resilient material, which when forward movement of the projectile ceases, is reconverted into kinetic energy effective to accelerate the projectile in a reverse direction. Thus, it is suggested, the force transmitted to the wearer at the innermost surface of the armor is the residue of force which has not been absorbed by compression of the resilient layers, and that such residual force is transmitted to the wearer over a very large area, compared to the area of the small plate originally struck by the projectile.
However, it can be demonstrated that as a practical matter, armor of the type discussed above cannot be employed as flexible light weight armor, which is effective against hard nosed projectiles traveling at a high velocity. In this respect, it is well known that presently available materials when formed into a small sized plate of the type proposed for use in the outmost layer of such armor are unable to withstand without complete failure due to melting or fracture, the impact of a hard nosed projectile traveling at high velocity. Accordingly, when armor of this type is struck with a hard nosed high velocity projectile, at least a plate in the first and probably several succeeding layers of plates will fail and be completely deformed before sufficient kinetic energy is absorbed or converted to heat, acoustical and plate deforming energies in order to permit a plate in an intermediate layer of the armor to move along with the projectile without itself being deformed. This in effect requires that in order to reduce to a minimum the energy transferred through the armor to a wearer, the number of plates layers must be increased over that required if no plate were to fail. However, the number of plate layers which may be employed, is severely limited by the requirement that the armor be flexible and lightweight. The problem as to flexibility will be appreciated when it is considered that when, as suggested in U.S. Pat. No. 2,723,214, the individual plate areas of successive layers increases as by a factor of 4, the probable practical limit is about 5 plate layers before the armor surface adjacent a wearer would become substantially rigid.
Further, it has been found that normally resilient material, incorporated within a composite armor, when struck by a high velocity projectile, acts adjacent to the outwardly facing surface of the armor as a rigid body and thus does not elastically compress so as to readily absorb and convert kinetic energy of the projectile to potential energy.
U.S. Pat. No. 4,186,648 to Clausen et al, which is herein incorporated by reference, discloses an armor structure in which the structure of the present invention may be incorporated. This patent teaches the use of a plurality of woven fabric laminates of polyester resin fibers arranged and supported in and by a resinous matrix.
U.S. Pat. No. 2,697,054 to Dietz et al discloses laminated plastic structures especially adapted for absorption of kinetic energy of shrapnel or the like.
U.S. Pat. No. 4,732,944 discloses ionomer resin films which are sold under the trademark NOVIFLEX by Artistic Glass Products Company, which are used in the present invention.